On Feb 29, 2008, at 11:32 AM, [EMAIL PROTECTED] wrote: > At long simulation times I observe an interesting effect of a non- > decaying > oscillatory mode within the calulated volume. The magnitude of the > oscillations remains at the level of 1e-4 - 1e-7 of the initial wave > magnitude.
When you say "oscillatory", do you mean oscillating in sign at every grid point? In the discretized Maxwell equations, waves oscillating at the Nyquist frequency have zero group velocity, so they can hang around a long time. To reduce your coupling into these high-frequency waves, you can turn on your source more smoothly, by increasing the "cutoff" parameter (for a gaussian or CW source). You could also experiment with turning off epsilon-averaging if that is causing instabilities. Steven _______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
